Catheter for electrophysiological procedures

ABSTRACT

A catheter adapted to perform electrophysiological procedures comprises a body member, a manipulation handle attached to the proximal end of the body member for applying torque to the body member, the handle having a control knob adapted for control movements in a first plane and in a second plane simultaneously. A deflection control line is attached at its distal end to the distal portion of the catheter and its proximal end attached to the control device of the handle so that tension applied to the control line by sliding the control knob causes deflection of the distal portion of the catheter. A stiffening member is disposed within the body member of the catheter and is slidable, said stiffening member providing increased rigidity to the portion of the body member in which the stiffening member is located. Rotation of the control knob controls the position of the stiffening member in the body member. In a further aspect, a stiffening member in accordance with one embodiment includes a tapered distal end section with a ball formed on the distal tip, the tapered section terminating at the ball. In accordance with another aspect, the torsional rigidity of the catheter body is increased by use of a layer of aramid fibers mixed with an epoxy. In yet another feature, the handle and rotatable sliding element are symmetrically shaped to facilitate complete single-handed operation of the handle by the physician of all position control aspects of the catheter.

This is a continuation of application Ser. No. 08/031,249, filed Mar.12, 1993, now U.S. Pat. No. 5,364,352.

BACKGROUND

The invention relates generally to catheters, and more particularly, tosteerable catheters for performing electrophysiological procedures, suchas mapping electrical signals emitted from conductive cardiac tissue andablating aberrant cardiac tissue at the point of arrhythmia originationin order to terminate the arrhythmia.

The heart beat in a healthy human is controlled by the sinoatrial node(S-A node) located in the wall of the right atrium. The S-A nodegenerates action potentials which are transmitted through pathways ofconductive heart tissue in the atrium to the atrioventricular node (A-Vnode) which in turn transmits the signals throughout the ventricle bymeans of the His and Purkinje conductive tissues. Improper growth of ordamage to the conductive tissue in the heart can interfere with thepassage of electrical signals from the S-A and A-V nodes resulting indisturbances to the normal rhythm of the heart, referred to as cardiacarrhythmia.

If the arrhythmia is refractory to medication, an alternative treatmentis to ablate the aberrant conductive tissue. However, that aberranttissue must first be located. One technique involves the electricalmapping of signals emanating from conductive cardiac tissue to locatethe aberrant tissue causing the arrhythmia. Ablution may then beperformed. Ablation of the aberrant conductive tissue usually controlsthe arrhythmia and allows the heart rhythm to return to an acceptablelevel.

One conventional method for mapping the electrical signals fromconductive heart tissue is to provide an array of electrodes on thedistal extremity of a catheter and place those electrodes in contactwith the interior of a patient's heart. Typically, the catheter isintroduced into the cardiovascular system of the patient through a bloodvessel and advanced to an endocardial site such as the atrium orventricle of the heart. When placed into the blood vessel, the cathetermust follow the irregularly shaped path defined by the blood vessel andbranch vessels until the distal end of the catheter reaches the desiredlocation. To assist in steering the catheter, some catheters have acurved distal tip. While this pre-formed curve may fit the curves ofsome blood vessels, it rarely fits all anatomical possibilities. Greaterfreedom of movement is desirable.

To achieve greater control over the movement of the catheter in steeringit through the cardiovascular system to the desired location in thepatient, prior catheters have Used guide wires to selectively vary theshape of the distal tip of the catheter. In another technique, a controlline is attached at a point adjacent the distal tip of the catheter.Pulling the proximal end of the control line causes the distal tip ofthe catheter to bend in one direction. Other designs have used multiplecontrol lines to obtain bending in multiple directions; however, thesize of the catheter increases. Larger catheters are undesirable due tothe difficulties involved in moving them through the patient'scardiovascular system and the increased blockage to blood flow. Whilethe control line approach provides increased freedom of control over themovement of the distal end of the catheter, its effect in priortechniques is limited to an arc with a fixed radius.

In another technique, a mandrel or guide wire is also located in thecatheter in addition to the control line and is moved to alter theradius of blend of the distal end of the catheter. The mandrel would bemoved more towards the distal end or more towards the proximal end ofthe catheter to alter the radius of bend of the distal end. While suchan approach has been found to yield improved control over the movementof the distal end, the disclosed technique required that the physicianuse two hands to exert this control. Additionally, no means wereprovided for holding the mandrel and control line in position once thedesired bend was obtained thereby resulting in the physician having tohold both the mandrel end and the operating mechanism of the controlline. Requiring the use of two hands for the steering function alonerestricts the physician from performing other tasks at the same time.

Another consideration in keeping the catheter small in size butproviding an increased steering capability is the torsional rigidity ofthe catheter. In catheters with low torsional rigidity, torsion mayaccumulate as the proximal end of the catheter is twisted by thephysician. Then as the distal end finally begins rotating, theaccumulated torsional moment will tend to unwind the catheter, resultingin rapid rotation of the tip inside the blood vessel. Such unwinding mayresult in the distal tip of the catheter overshooting the branch vesselentrance then requiring further steering manipulation on the part of thephysician lengthening the procedure. Thus it is desirable to haveincreased torsional rigidity of the catheter so that rotating theproximal end of the catheter will result in immediate rotation at thedistal end; i.e., immediate torque reaction.

A further consideration in navigating the catheter into the desiredposition in the patient is the bending rigidity or stiffness of thecatheter. In some cases, increased force is required to advance thedistal end of the catheter through a certain vessel position or to holdit against a particular site such as buttressing the catheter against awall of the aorta or against a valve lip. However, decreased bendingrigidity is beneficial in some cases. Therefore it would be desirable toprovide variable bending rigidity of the catheter to provide increasedsteering and positioning control. Such a feature would be desirable inan electrophysiological procedure catheter due to the requirement fornavigation completely into the heart and for continued contact withparticular tissue during the beating action of the heart. Additionally,it would be desirable to incorporate the control means over the bendingrigidity of the catheter into the same control device as is used for theother steering mechanisms.

Frequently, the position of the distal portion of the catheter withinthe heart may have to be adjusted one or more times in order to providea complete and comprehensive view of the signals from the electricallyconductive heart tissue which is necessary to detect the point where thearrhythmia originates. Once the origination point for the arrhythmia isdetermined, the conductive heart tissue at the site can be ablated. RFheating is one technique typically used for ablation. Successfulablation of the conductive tissue at the arrhythmia initiation siteusually terminates the arrhythmia or at least moderates the heart rhythmto acceptable levels. Increased and easier control over the steering andpositioning of the catheter would facilitate the mapping and ablation ofthe heart tissue.

Hence, those skilled in the art have recognized the need for a catheterfor use in electrophysiological procedures which provides increasedcontrol over steering and positioning the catheter while not increasingthe size of the catheter. It has also been recognized as desirable acatheter with increased torsional rigidity and a means for providingincreased control over the axial rigidity of the catheter. The presentinvention fulfills these needs and others.

SUMMARY

Briefly and in general terms, the present invention is directed to acatheter which is adapted to perform electrophysiological procedures,such as detecting arrhythmia and ablating conductive pathways within apatient's myocardium in order to control arrhythmia. The cathetercomprises a body member; a manipulation handle attached to the proximalend of the body member for applying torque to the body member, thecatheter body being attached to the handle such that when the handle isrotated about its longitudinal axis, the body member rotates about itslongitudinal axis in response. The handle also has a control deviceadapted for control movements in a first plane and in a second planesimultaneously.

A deflection control line is slidable in a direction parallel to thelongitudinal axis of the body member and has its distal end attached tothe distal portion of the catheter and its proximal end attached to thecontrol device of the handle so that tension applied to the control lineby movement of the control device in the first plane will cause thedeflection of the distal portion of the catheter.

A stiffening member is disposed within the body member of the catheterand is slidable in a direction parallel to the longitudinal axis of thebody member, said stiffening member providing increased rigidity to theportion of the body member in which the stiffening member is located.Additionally, the stiffening member is connected at its proximal end tothe control device of the handle such that movement of the controldevice in the second plane controls the position of the stiffeningmember in the body member. In a further aspect, a stiffening member inaccordance with one embodiment includes a tapered distal end sectionwith a ball formed on the distal tip, the tapered section terminating atthe ball. The tapered section permits easier bending of this portion ofthe stiffening member so that as it is advanced into the body member, itmay negotiate a bend in a catheter which is already in position. Theball protects the body member of the catheter from being pierced by thestiffening member as the stiffening member is advanced and contacts abend in the body member.

The deflection control line may be a wire or cable which is slidablydisposed in the body member of the catheter. An open channel may beformed entirely within an inner tubular member of the body member, ormay be formed in the exterior of the tubular member, and extends to theflexible distal portion of the catheter shaft where the distal end ofthe control line is attached. Tension applied to the control line by thephysician operating the control device causes the flexible distalportion of the catheter shaft to be deflected from the centrallongitudinal axis of the catheter shaft and thereby allows the physicianto control the shape of the distal extremity during the procedure whichin turn facilitates steering through blood vessels and placement of thedistal extremity against the cardiac tissue within the patient's heart.The anchoring element may be a plate fixed within a transverse plane inthe distal portion of the catheter shaft or a cylindrical memberdisposed about the inner tubular member.

In accordance with another aspect, a torsion device for increasing thetorsional rigidity of the catheter body is coupled with the body memberof the catheter so that torque applied to the proximal end of the bodymember will be rapidly reflected at the distal end. In a further aspect,this torsional device comprises a layer of aramid fibers mixed with anepoxy, the layer being located within the body member such that rotatingthe handle results in rapid rotational response at the distal end of thecatheter. Movement of the handle in a rotational sense controls therotational position of the distal end of the catheter and movement ofthe handle in a longitudinal sense control the longitudinal position ofthe distal end of the catheter.

The handle control device may comprise a rotatable slide element, therotation of which advances or retracts the stiffening element and thesliding action of which applies or releases tension on the control line.In another feature, the range of movement of the rotatable slidingelement and the coupling of the control line thereto are selected toresult in a complete release of tension on the control line when therotatable sliding element is at one end of the range of sliding movementthereby permitting the body member to resume its substantially straightform. The range of movement caused by rotation of the rotatable slideelement is also selected to permit positioning the stiffening member ata first position resulting in a first radius of curvature of the distalend of the body member when tension is applied to the control line, andat the other end of the range, in positioning the stiffening member at asecond position resulting in a second radius of curvature of the distalend of the body member when tension is applied to the control line. Thesecond radius of curvature is different from the first radius. Atpositions in between the respective ends of the ranges, various bendsare possible and the bending of the distal end of the catheter iscontinuously variable between the ends of the ranges. In a furtheraspect, the positioning of the stiffening rod controls the bendingstiffness of the body member and the range of movement of the controldevice is selected to achieve a predetermined range of bending rigidity.

In yet another feature in accordance with the principles of theinvention, the handle and rotatable sliding element are symmetricallyshaped to faciliate complete single-handed operation of the handle bythe physician including rotation of the handle, longitudinal movement ofthe handle, rotation of the rotatable sliding element, and sliding ofthe rotatable sliding element. The handle itself may be rotated aboutits longitudinal axis while the sliding element is being both rotatedand slid. Additionally, the handle is shaped for ease in grasping andretention by the physician's hand and further, the rotatable slidingelement is shaped so that it may be both rotated and slid by the digitsof that same hand. The sliding element in one aspect, has a grooveformed about the outside and the two surfaces on either side of thegroove are conveniently used by the operator to control sliding movementof the element.

The handle may also contain indicia, such as a colored band positionedon the handle body, to indicate movement of the rotatable slide elementbeyond a preselected point. The handle may also include gradations toprovide a visual reference system to indicate the present position ofthe rotatable sliding element in its range of movement.

The catheter may have one or more electrodes on a distal portion, andmay have an ablation electrode provided on the distal tip for ablationof cardiac conductive pathways. One or more electrical conductors extendwith in the body member and are electrically connected to the electrodeson the distal portion of the catheter. Additional electrical conductorsextend within the body member to electrically connect the ablationelectrode to an electrical source, preferably a high frequencyelectrical source, for providing the ablation energy.

The catheter of the invention allows a physician to effectively controlthe shape and stiffness of the catheter during electrophysiologicalprocedures, including the detection and ablation of aberrant conductivecardiac tissue. The catheter of the present invention can be more easilymanipulated within a patient's heart and allows the physician to moreaccurately place the catheter electrodes as desired. Other aspects andadvantages of the invention will become apparent from the followingdetailed description and accompanying drawings, illustrating by way ofexample the features of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevation view of an electrophysiological catheterembodying features of the invention;

FIG. 2 is an enlarged longitudinal cross-sectional view of the distalportion of the catheter along lines 2--2 shown in FIG. 1;

FIG. 3 is a transverse cross-sectional view of the distal portion of thecatheter shown in FIG. 2, taken along the lines 3--3;

FIG. 4 is a schematic elevation view of a distal portion of the cathetershown in FIG. 1 with tension applied to a control line which extendsinto the distal portion of the catheter;

FIG. 5 is a schematic elevation view of a distal portion of the cathetersimilar to that shown in FIG. 4 except that a stiffening rod is advancedinto the distal portion of the catheter shaft in addition to tensionbeing applied to the control line;

FIG. 6 is a schematic elevation view of a distal portion of the cathetersimilar to that shown in FIG. 5 except that the stiffening rod isadvanced farther into the distal portion of the catheter than that shownin FIG. 5;

FIG. 7 is a transverse cross-sectional view of an alternative embodimentincorporating principles of the invention;

FIG. 8 is an enlarged longitudinal view, partially in section, of amanipulating handle secured to the proximal end of the catheter as shownin FIG. 1;

FIG. 9 is an exploded perspective view of the manipulating handle shownin FIG. 8;

FIG. 10 is a perspective view of the distal portion of the cathetershown in FIG. 1 with the jacket and a distal extremity cut away toillustrate the connection of the deflection control line to the anchorplate;

FIG. 11 is a perspective view of the distal portion of an alternativecatheter with the jacket and a distal extremity cut away to illustratethe connection of the deflection line to an anchor cylinder;

FIG. 12 is a perspective view of the catheter shown in FIG. 1; and

FIG. 13 is a view of the distal end of a tapered stiffening memberhaving a ball formed on the distal tip.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings with more particularity, wherein likereference numerals designate like or corresponding elements among theseveral views, there is shown in FIGS. 1-3, a catheter 10 usable forelectrophysiological procedures and embodying features of the invention,including an elongated shaft or body member 11, a plurality of sensingelectrodes 12 on the exterior of the body member along the distalportion 13 thereof and an ablation electrode 14 at the distal tip of thebody member 11. The tip electrode functions both as an ablationelectrode and as a sensing electrode; thus, both numerals 12 and 14 arepointing to it. The body member 11 has an inner lumen 15 which extendsto the distal tip and which has disposed therein an electrical conductor16 having a distal end electrically connected to the ablation electrode14. Also extending within the inner lumen 15 are a plurality ofelectrical conductors 17 which have distal ends electrically connectedto the sensing electrodes 12. Although three sensing electrodes 12 andone ablation electrode 14 are shown, this is for purposes ofillustration only and is not meant to be restrictive of the invention.More or fewer of each of these electrodes may be used depending on theapplication. Additionally, the types of devices mentioned for sensingand ablation are for also only for purposes of illustration. Forexample, rather than using an "electrode" for ablation, a different typeof energy transducer may be incorporated into the catheter.

The catheter body member 11 has a deflection control system 18 which hasa distal end located at the distal portion 13 of the body member 11. Thedeflection control system 18 preferably comprises a control line ordeflection wire 23 and a lubricous coating or jacket 24, e.g. a suitablefluoropolymer such as poly(tetrafluoro)ethylene which is available underthe trademark Teflon® from E. I. duPont, deNemours & Company. Otherfluoropolymers and other lubricous materials may be utilized to coat thedeflection wire 23. The jacket 24 may be a lubricous sheath which allowsfor the movement of the deflection wire 23 therein. The deflection wire23 is fixed to an anchor member 19 in the distal portion 13 so that,when tension is applied to the deflection wire 23 by means of themanipulating knob 43 mounted on the handle 20 at the proximal end of thecatheter body member 11, the flexible distal portion 13 of the bodymember 11 will be deflected from its at rest position as shown in FIGS.1 and 2 to the curved shape shown in FIG. 4. Preferably, the deflectioncontrol system 18 is disposed within a lumen 21 formed in the catheterbody member 11 so as to be off-set from the central longitudinal axis 22of the catheter body member 11 to more easily effect the deflection ofthe flexible distal portion 13. In the preferred embodiment shown in thefigures, the body member 11 is constructed so that it is substantiallystraight when at rest and returns to that position when bending forceshave been removed. The deflection control system 18 is used to impartsuch bending forces.

FIGS. 1 and 2 illustrate a presently preferred embodiment of theinvention wherein the catheter body member 11 has an inner tubularmember 25 with the inner lumen 15 extending therein, an outer jacket orcoating 26 on the exterior of the body member and a reinforcing tubularstructure or layer 27 disposed between the outer jacket or coating 26and the inner tubular member 25. The layer 27 is formed ofmulti-filament strands 28 within a polymeric matrix 29. Preferably, thereinforcing multi-filament strands 28 are braided as shown schematicallyin FIGS. 3 and 7. It has been found that this construction providesimproved torsion rigidity along the entire length of the body member 11proximal to the relatively short, flexible distal portion 13. Thus, thetorque developed by rotating the manipulation handle 20 at the proximalend of the body member 11 will be quickly communicated to the distal endand the torsion storage problems experienced in the prior art arelessened. The tubular reinforcing structure 27 terminates at a locationproximal to the distal tip of the body member 11 to provide thedeflectable distal portion 13 with more flexibility.

A mandrel or stiffening member 31 is slidably disposed within a sheath30, preferably formed of a fluoropolymer such as Teflon, both of whichare disposed in the inner lumen 15 of the inner tubular member 25. Thestiffening member is preferably formed of stainless steel, althoughother materials may function as well. The advancement of the stiffeningmember 31 within the distal portion 13 of the catheter body member 11controls the stiffness of the distal portion and in conjunction with thedeflection wire 23 controls the shape of the flexible distal portion asshown in FIGS. 4-6.

In FIG. 4 the stiffening member 31 is shown completely withdrawn fromthe distal portion 13 of the catheter body member 11 so that tensionapplied to the deflection wire 23 will result in the curvature of thedistal portion 13 as shown. In the case shown in FIG. 5, the stiffeningmember 31 has a tapered end thus making that section more "bendable" andhas been advanced into the distal portion 13. The tapered part of thestiffening member 31 has been bent and the curvature of the distalportion 13 is altered. Two radii of curvature are shown thus resultingin increased steering capability.

As depicted in FIG. 6, the stiffening member 31 is more stiff and hadbeen advanced even farther into the distal portion 13 of the body member11. The curvature is altered again. The portion 32 of the body memberwhich extends distal to the location of the anchor member remainsessentially straight.

FIG. 13 presents an enlarged view of the stiffening member 31 of FIG. 5.In accordance with this embodiment, the stiffening member 31 includes atapered section 76 ending at a ball 78. The ball 78 will protect thecatheter body from being pierced by the stiffening member from theinside such as in the case where the catheter has already been put intoa curved configuration and the stiffening member is being advanced intothat curved section of the catheter to obtain increased bendingstiffness distally. Such may occur where the distal section 32 of thecatheter will not remain in position against certain tissue due to heartmovement. Rather than piercing the body member, the rounded distal tipof the stiffening member Will negotiate the curve of the body member.The remainder of the stiffening member 31 will then follow. The taperedsection 76 likewise assists the stiffening member 31 in negotiatingalready established bends in the catheter. Because the tapered sectionis of a smaller diameter, it will bend more easily thus enabling thedistal end of the stiffening member to bend around the existing catheterbend more easily. As mentioned above, a further advantage of the taperedsection/ball combination is shown in FIG. 5 where different radii ofbends are possible thereby giving the physician greater steeringcontrol.

The deflection wire 23, the stiffening member 31, and the torque controllayer 27 resulting in additional torsional rigidity, allow the physicianusing the catheter to more easily and accurately advance the catheterthrough a patient's vascular system into the beating heart. Thephysician can more easily adjust the shape and stiffness of the distalportion 13 of the catheter 10 to place the distal portion at a desiredlocation against a ventricle wall for example in a desired orientation.This degree of control provides the physician with greater versatilityin accurately plating the catheter at the desired location in order tobetter determine the site from which the arrhythmia originates and tomore accurately place the ablation electrode against the originatingsite of the arrhythmia to effectively ablate the conductive tissue atthe site to eliminate or moderate the arrhythmia while the heart isbeating. The position of the stiffening member 31 may be adjusted toresult in greater or lesser bending stiffness as required. For example,when the catheter is placed against a beating heart and increasedbending stiffness is needed to keep it in position, such stiffness maybe attained by advancing the stiffening member towards the distal end ofthe catheter. Where less bending stiffness is required, the stiffeningmember may be retracted towards the proximal end of the catheter.

FIG. 7 illustrates an alternative embodiment to the catheter body member11 construction shown in FIGS. 1--3. In this embodiment, the innertubular member 25 is provided with a plurality of open channels formedin its exterior which are adapted to receive the electrical conductors16 in addition to a plurality of deflection control systems 18. In thisembodiment four sensing electrodes are provided on the distal portion ofthe catheter. The electrical conductor 17 connected to the ablationelectrode 14 is shown extending through the central inner lumen 15.However, it may be disposed within a different channel which may beformed in the exterior of the tubular member 25 in order to provide astiffening member within the inner lumen 15 as in the previouslydiscussed embodiment. The channels are closed by the tubular layer 27.

The details of the manipulating handle 20 on the proximal end of thecatheter 10 are shown in detail in FIGS. 8 and 9. The handle 20generally includes a body 40, a tubular body member 41 having a proximalend seated within a recess provided within the body. A slide element 43is slidably mounted about the cap 42 and an elongated female threadedelement 44 which acts as a nut and which rotates within the body 40. Thedistal portion of the female threaded element 44 is provided with aplurality of longitudinally extending ridges 45 on the exterior thereofwhich are adapted to be slidably received within the interior surface ofthe slide element 43. Therefore, rotating the slide element 43 willcause rotation of the threaded element 44. A hollow male threadedelement 47 is slidably disposed about the body member 41 and isthreadably engaged within the female threaded element 44. The malethreaded element 47 has an inward projection 48 to which the proximalend of the stiffening elements 31 is suitably secured such as bycrimping or insert molding. A ring 49 is seated within a shoulder 50provided on the interior of the slide element 43 and the ring 49 has aninward projection 51 to which is secured the proximal end of thedeflection wire 23. In the preferred embodiment, the shoulder is formedby two parts fastened together by screws as shown in FIG. 8. The inwardprojections 48 and 51 are located in the longitudinal slot 60 in theshaft 41, and are thus restricted from rotating. The proximal end of thecatheter body member 11 is secured to the cap 42 such as by adhesive.Therefore, rotating the handle 20 will result in rotation of the bodymember 11.

Longitudinal movement of the slide element 43 in the proximal directionby an operator will move the ring element 49 longitudinally in theproximal direction causing tension to be applied to the deflection wire23 which is secured to the inward projection 51 of the ring 49 andthereby curves the distal portion 13 of the catheter body member 11.Longitudinal movement in the distal direction will lessen the tensionapplied to the deflection wire 23 and allow the distal portion 13 toreturn to its normal shape, which is usually straight. The slide element43 includes a groove 62 into which the digit or digits of the operatormay reside when moving the element. The surfaces 64 and 66 on eitherside of the groove would be used to receive the force applied by theoperator's digits to move the slide element 43. This results in morepositive control over the slide element and increased convenience inoperation.

Rotation of the slide element 43 by the operator will rotate the femalethreaded element 44, which in turn will move the hollow male threadedelement 47 along the body member 41 and result in the longitudinalmovement of the stiffening member 31 which is connected to the inwardprojection 48 on the male threaded element 47. The stiffening member 31must have sufficient column strength to communicate the thrust appliedto the proximal end to the distal end thereof and to otherwise stiffenthe distal portion 13 of the catheter body member 11.

Turning briefly to FIG. 12, the movement of the knob 43 in two planescan be seen. In the first plane 62, the knob 43 slides in a directionparallel to the longitudinal axis of the catheter 20 for control overthe deflecting wire 23, as shown by the arrows 65 drawn in parallel withthe longitudinal axis. In the second plane 66, the knob 43 rotates asshown by the curved arrows 68, to control the position of the stiffeningmember. These planes are perpendicular to each other in this view. Itmay also be noted that the handle body 40 includes a larger diameterportion 70 at its proximal end. The body 40 is smoothly tapered up tothat enlarged diameter portion 70. The existence of this enlargedportion 70 provides a physical indicator to the physician as to thelocation of his or her hand on the handle 40. The physician can tell howfar back his or her hand is on the handle based on the feeling impartedto the hand by the differences in diameter along the handle.

The cap 42 or female threaded element 44 may include indicia, such asthe color red, placed at a certain point on its outer surface toestablish a position reference system. Upon moving the slide element 43far enough distally to reveal the red indicia on the cap, the operatorwould then be made aware that he or she has reached a predeterminedposition. Alternately, the indicia may include gradations marked on thecap.

Electrical conductors 16 and 17 (not shown in FIG. 8 or 9) pass throughthe inner lumen 52 of the tubular shaft 41 and are electricallyconnected to the electrical connector 53 shown on the proximal end ofthe handle 20 in FIG. 8. A suitable connector 53 is the Model NO.V114RC72 sold by Alden Products Company, located in Brockton, Mass.Other suitable electrical connectors are commercially available.

In one presently preferred embodiment of the invention, the tubularsheath member 24 about the deflection wire 23 has an outer diameter ofabout 0.015 to about 0.020 inches (0.38 to 0.51 mm) and an innerdiameter of about 0.008 to about 0.012 inches (0.20 to 0.31 mm). Thelayer 27 formed of multifilament strands 28 and polymer matrix 29 has awall thickness of about 0.003 to about 0.005 inches (0.08 to 0.013 mm)and the outer jacket or coating 26 has a wall thickness of about 0.004to 0.007 inches (0.10 to 0.18 mm). The outer diameter of the cathetermay range from about 0.079 to about 0.12 inches (2.01 to 3.05 mm) andthe overall length of the catheter 10 may range from about 39.4 to 51.2inches (100 to about 130 cm). The sensing electrodes 12 on the distalend are preferably formed of platinum or a platinum alloy and are about0.030 to 0.079 inches (0.75 to about 2.0 mm) in with and are spacedalong the length of the distal portion about 0.079 to 0.394 inches (2 toabout 10 mm) apart. A preferable spacing is about 0.20 inches (5 mm).The ablution electrode which is about 0.16 inches (4 mm) long is alsopreferably formed of platinum or a platinum alloy, or platinum coatedstainless steel.

The inner tubular member 25 is formed from a thermoplastic elastomerhaving a Shore hardness from about 75A to about 75D, preferably about85A to about 55D and is preferably a thermoplastic polyurethane.Suitable polyurethanes include Tecothane® which is available fromThermedics, Inc. Alternative materials include Pebax® which is athermoplastic elastomer available from the Atochem Company. The polymermatrix 29 is formed of a thermosetting polymer and preferably is anepoxy adhesive such as FDA2. The multi-filament strands 28 may be formedof high strength polymeric materials such as aramid (Kevlar®) availablefrom E. I. duPont, deNemours & Co., Inc. The fibrous strands compressinto a ribbon-like shape when braided.

The outer jacket or coating 26 is preferably formed of a thermoplasticpolymeric material having a Shore hardness of about 85A to about 75D,preferably about 95A to about 65D. Suitable polymers include apolyurethane made with a polytetramethylene glycol ether which isavailable commercially as 2363 55DE Pellethane from the Dow ChemicalCompany or a polyurethane such as TT 2055D B320 Tecothane which isavailable from Thermedics. Other suitable thermoplastic polymericmaterials may be employed.

Both the inner tubular member 25 and the outer jacket 26 may haveincorporated therein a radiopaque material such as barium sulfate tofacilitate the fluoroscopic observation during the procedure by thephysician in attendance.

The electrical conductors 16 and 17 may be 30-40 awg copper wires with asuitable insulation, such as a polyamide, polyurethane/nylon, or afluoropolymer such as poly(tetrafluoro)ethylene. The deflection wire 23and stiffening member 31 are formed of a stainless steel suitable for invivo use. The deflection wire 23 is about 0.005 to about 0.010 inch(0.127 to 0.254 mm) in diameter and the stiffening member 31 is about0.010 to about 0.020 inch (0.254 to 0.508 mm) in diameter, and thelengths thereof are appropriate for the catheter in which they areutilized.

The catheter 10 can be conveniently made by the following procedure.Multi-filament strands 28 are braided about the inner tubular member 25along the length thereof. The braiding may be terminated short of thedistal portion 13 or the entire length of the inner tubular member 25may be braided and the braided portion on the distal portion 13 may beremoved. Matrix 29 is formed either by impregnating the braided productwith a suitable impregnate or incorporating matrix material with thestrands prior to braiding and then heating the braided product to formthe matrix. To complete the catheter body member, a heat shrinkablethermoplastic tubular member or sleeve which forms the outer jacket 26is fitted onto the braided and impregnated reinforcing layer 27, andthen a heat shrinkable tubular element (not shown) is fitted over thethermoplastic tube forming the outer jacket 26 and the assembly is thenheated by hot air to shrink the heat shrinkable tube and press thethermoplastic tube against the exterior of the reinforcing layer 27 tosecure the jacket 26 thereto. Upon cooling, the heat shrinkable tube isstripped off and discarded and the catheter is then ground to thedesired outer diameter.

Electrical conductors 16 and 17 are advanced through the inner lumen 15of the inner tubular member 25 and electrically connected by solderingto the sensing electrodes 12 and the ablation electrode 14 respectively.The electrodes 12 are slid over the distal position 13 and secured tothe exterior thereof by a suitable adhesive. Ablation electrode 14 issimilarly secured to the distal tip of the catheter after conductor 17is soldered thereto. The stiffening member 31 is passed proximallythrough the inner lumen 15 and is secured by its proximal end to theinward projection 48 on the male threaded element 47 on the manipulatinghandle 20 by suitable means such as brazing or soldering or by anadhesive. The deflection wire 23 is advanced through the lumen 21. Theproximal end of the deflection wire 23 is secured by the same or similarmeans to the inward projection 51 on the ring 49. The distal end of thedeflection wire 23 is secured by the same or similar means to the anchorplate 19 as shown in FIG. 10. In this instance a transverse slit isformed in the distal portion 13, the anchor plate 19 is adhesivelybonded to the proximal facing of the slit and then the distal facing ofthe slit is adhesively bonded to the anchor plate and the proximalfacing of the slit. An alternative embodiment is shown in FIG. 11wherein an anchor cylinder 55 is provided Which encircles and is securedto the inner tubular member 25, and has a linear depression or groove 56which is seated into the open channel 30. In the latter instance, thedeflection wire 23 is suitably secured such as by soldering within thegroove 56. The anchor plate 19 and the anchor cylinder 55 may be formedof suitable high strength material such as stainless steel.

While the invention has been described herein in terms of certainpreferred embodiments, those skilled in the art of catheters forperforming electrophysiological procedures within a patient willrecognize that various modifications and improvements can be made to theinvention without departing from the scope thereof. Although preferredand alternative embodiments of the invention have been described andillustrated, it is clear that the invention is susceptible to numerousmodifications and adaptations within the ability of those skilled in theart and without the exercise of inventive faculty. Thus, it should beunderstood that various changes in form, detail and usage of the presentinvention may be made without departing from the spirit and scope of theinvention.

What is claimed is:
 1. A catheter comprising:a body member having adistal end and a proximal end; a deflection control line slidable in adirection parallel to the longitudinal axis of the body member, thecontrol line having a distal end attached to the body member whereinmovement of said deflection control line controls deflection of thedistal end of the body member; and a stiffening member disposed withinthe body member and slidable in a direction parallel to the longitudinalaxis of the body member, said stiffening member providing increasedrigidity to the portion of the body member in which the stiffeningmember is located.
 2. The catheter of claim 1, further comprising amovable control device mounted to the body member and connected to thestiffening member, and further being adapted for a range of selectivemovement in relation to the body member, wherein selective movement ofthe control device controls the position of the stiffening member in thebody member.
 3. The catheter of claim 2, wherein the control device isadapted for rotational movement wherein selective rotational movement ofthe control device controls the position of the stiffening member in thebody member.
 4. The catheter of claim 2, further comprising a handleconnected to the proximal end of the body member wherein the movablecontrol device is mounted to the handle and has a plurality of positionswithin its range of selected movement, wherein the handle comprisesindicia formed on said handle and located within the range of selectedmovement of the control device to indicate the position of the controldevice.
 5. The catheter of claim 4, wherein the indicia indicate thesliding position of the control device.
 6. The catheter of claim 4,wherein said indicia comprise gradations.
 7. The catheter of claim 4,wherein said indicia comprise a colored band to indicate movement of thecontrol device beyond a preselected position.
 8. The catheter of claim4, wherein the indicia indicate the rotational position of the controldevice.
 9. The catheter of claim 1, further comprising a movable controldevice mounted to the body member and further being adapted for a rangeof selective movement in relation to the body member, wherein thedeflection control line has a distal end fixedly attached to a distalportion of the body member and a proximal end attached to the controldevice so that tension applied to the control line by selective movementof the control device will cause deflection of the distal portion of thecatheter.
 10. The catheter of claim 9, wherein the control device isadapted for a range of selective movement in relation to the body memberand the control device is mounted to a proximal end of the stiffeningmember wherein selective movement of the control device controls theposition of the stiffening member in the body member.
 11. The catheterof claim 10, wherein the control device is adapted for selectivesimultaneous sliding and rotating movement.
 12. The catheter of claim11, wherein the stiffening member is connected to the control devicesuch that rotating movement of the control device controls the positionof the stiffening member in the body member.
 13. The catheter of claim12 wherein sliding movement of the control device controls the tensionapplied to the control line.
 14. The catheter of claim 11 whereinsliding movement of the control device controls the tension applied tothe control line.
 15. The catheter of claim 9 wherein sliding movementof the control device controls the tension applied to the control line.16. The catheter of claim 9 further comprising a handle connected to theproximal end of the body member wherein the control device is mounted tothe handle and has a plurality of positions within its range of selectedmovement, wherein the handle comprises indicia formed on said handle andlocated within the range of selected movement of the control device toindicate the position of the control device.
 17. A catheter comprising:abody member having a distal end and a proximal end; a deflection controlline disposed within the body member and slidable in directions parallelto the longitudinal axis of the body member, wherein movement of saiddeflection control line controls deflection of the distal end of thebody member; a stiffening member disposed within the body member andslidable in directions parallel to the longitudinal axis of the bodymember, said stiffening member providing increased rigidity to theportion of the body member in which the stiffening member is located; ahandle connected to the proximal end of the body member; and a movablecontrol device adapted for selective movement, wherein the movablecontrol device is mounted to the handle and has a plurality of positionswithin a range of selected movement,wherein the handle comprises indiciaformed on said handle and located within the range of selected movementof the control device to indicate the position of the control device.18. The catheter of claim 17, wherein said indicia comprises visiblegradations.
 19. The catheter of claim 17, wherein said indicia comprisesa colored band to indicate movement of the control device beyond apreselected position.
 20. The catheter of claim 17, wherein the controldevice is adapted for selective simultaneous sliding and rotatingmovement.
 21. The catheter of claim 20, wherein the indicia indicatesthe rotational position of the control device.
 22. The catheter of claim20, wherein the indicia indicates the sliding position of the controldevice.
 23. A catheter comprising:an elongated body member having adistal portion and a proximal portion; an elongated first device movablymounted in said body member, movement of said first device providingselectively varying stiffness of the body member in accordance with thelocation in the body member of the first device; and an elongated seconddevice movably mounted in said body member, movement of said seconddevice in relation to the body member providing independent selectivelyvariable deflection of the distal portion of the body member inaccordance with said movement.
 24. The catheter of claim 23, furthercomprising a movable control device mounted to the body member andconnected to the first and second devices and being adapted forselective movement, wherein selective movement of the control device ina first direction variably controls the position of the first devicethereby controlling stiffness of the body member, and selective movementof the control device in a second direction independently controls theposition of the second device thereby controlling said deflection of thedistal portion of the body member.
 25. The catheter of claim 24, whereinthe control device is adapted for selective simultaneous sliding androtating movement.
 26. The catheter of claim 25, wherein slidingmovement of the control device controls the stiffness of the bodymember, and rotational movement of the control device controls thedeflection of the distal portion of the body member.
 27. The catheter ofclaim 23, further comprising a handle connected to the proximal end ofthe elongated body member;wherein the movable control device is mountedto the handle and has a plurality of positions within a range ofselected movement, wherein the handle comprises indicia formed on saidhandle and located within the range of selected movement of the controldevice to indicate the stiffness of the body member.
 28. The catheter ofclaim 27, further comprising indicia formed on the handle to indicatethe deflection of the distal portion of the body member.
 29. A cathetercomprising:a body member having a distal end and a proximal end; astiffening member disposed within the body member and slidable in adirection parallel to the longitudinal axis of the body member, saidstiffening member providing increased rigidity to the portion of thebody member in which the stiffening member is located; and a rotatablecontrol device adapted for selective rotation, wherein the stiffeningmember is connected at its proximal end to the control device such thatrotating movement of the control device controls the position of thestiffening member in the body member.
 30. The catheter of claim 29,further comprising a handle connected to the proximal end of the bodymember;wherein the control device is mounted to the handle and has aplurality of positions within a range of selected movement; wherein thehandle comprises indicia formed on said handle and located within therange of selected movement of the control device indicating the positionof the stiffening member in the body member.